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#1 |
Registered User
Join Date: Aug 2007
Location: orlando
Posts: 456
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Suggestions RE: Oil Fouled Plugs
I have a '72 402BB. On the passenger side bank the plugs continue to foul out & build up with what appears to be more like oil than carbon. The first plug (front) isn't too bad, but they get worse till the rear plugs are really caked up. I do have "colder" plugs to install, but if the left bank is fine, I don't think installing a colder range plug will remedy this. I think its a more serious issue. My question is; how do I determine if it's valves, valve seals, or rings?
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A man's thoughts devise his ways; but it's GOD that directs his steps. |
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#2 |
fat old dude
![]() Join Date: Feb 2010
Location: fresno, california
Posts: 1,424
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Re: Suggestions RE: Oil Fouled Plugs
i used non foulers for a bit.
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1972 c-10 shortbed 350/400 build thread http://67-72chevytrucks.com/vboard/s...d.php?t=389157 1968 workhorse http://67-72chevytrucks.com/vboard/s...d.php?t=446216 Accepting part donations |
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#3 | |
Registered User
Join Date: Mar 2011
Location: Los Angeles, CA
Posts: 152
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![]() Quote:
The valve seals are an easy enough fix as their replacement can be done with the heads on if you have an air compressor that puts out 150 PSI and have a air hold ( WMR-W84003 $9.95 ) and head-on valve spring compressor ( SUM-906784 $44.95 ). These are Summit Racing part numbers / prices. |
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#4 |
1969 Custom 30 wrecker
Join Date: Sep 2001
Location: Pottsville, Pa
Posts: 2,611
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Re: Suggestions RE: Oil Fouled Plugs
Could also be the intake gasket is allowing oil to be sucked in from the lifter galley into the intake ports.
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Bob 63 Impala 283/PG/3.36 (under restoration) 66 Impala 327/PG/3.36 66 Chevelle SS 409/M22/3.55 69 Chevelle 307/PG/3.08 (future restoration) 69 C10 short stepside 454/TH350/3.73 69 Custom 30 tow truck 350/4 spd/4.10 (resto done, CRUISIN TIME!) 71 Cheyenne 20 fleetside 350/4 spd/4.10 71 Chevelle 6/PG/3.08 72 Chevelle 454/M21/4.10 |
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#5 |
Senior Member
Join Date: Jul 2001
Location: Muskegon,MI,USA
Posts: 6,026
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Re: Suggestions RE: Oil Fouled Plugs
As mentioned it is probaly valve seals but make sure the drains in the heads are not plugged causing a ponding of oil in the valve cover.
Jim
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1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC |
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#6 |
Registered User
Join Date: Aug 2007
Location: orlando
Posts: 456
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Re: Suggestions RE: Oil Fouled Plugs
My apoligies guys. I neglected to mention I overhauled it about 4000 miles ago. So I don't think it's the valve seals or plugged oil returns.
I'm waiting for a borrowed compression tester to get here. I want to see if the cylinders are close to a "normal" reading. It's only (at this point) the left bank (passenger side). And the fouling gets worse from front to back.
__________________
A man's thoughts devise his ways; but it's GOD that directs his steps. |
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#7 |
Registered User
Join Date: Oct 2005
Location: Overland Park, Ks.
Posts: 5,216
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Re: Suggestions RE: Oil Fouled Plugs
If its an auto trans. Check the modulator. It can suck iol out of the trans. The vacuum usually feeds off the rear port in the intake.
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